# Diality Secure DataMatrix (Qt 5.15 + qmake + OpenSSL) — TLV + Auto-fit

Applied improvements:
- Payload redesigned as compact **TLV** (UTF-8 strings)
- Optional **compress-before-encrypt** (qCompress) when it actually reduces size
- PC tool auto-computes **pixels/module** to fit a target size (default 14.4mm) at a given printer DPI (default 300)
- Quiet zone reduced to **1 module**

## PC input format
Enter fields like:
- PID=CARTRIDGE-123|LOT=A24X7|EXP=20271231|SN=0000009876543210

EXP can also be YYMMDD (e.g., 271231).

## keys.json locations
- PC tool: `<app_dir>/keys.json`
- Device reader: `/etc/diality/keys.json` (fallback `<app_dir>/keys.json`)

## Dependencies
- Qt 5.15 (Widgets)
- OpenSSL (libssl + libcrypto)
- ZXing-C++ (PC tool only)

## qmake variables
- OPENSSL_INCLUDE_DIR
- OPENSSL_LIB_DIR
- ZXING_INCLUDE_DIR
- ZXING_LIB_DIR